Field of the Invention
The present invention relates to an apparatus, a method, and a storage medium storing computer program product for controlling imaging by using a plurality of operating systems (OS).
Description of the Related Art
Conventionally, there has been a digital camera that includes a real-time operating system (hereinafter, referred to as an RTOS) and a general-purpose operating system (hereinafter, referred to as a general-purpose OS). The RTOS has a function of controlling a task to execute and includes a function and property for executing processing with time constraints. For this reason, the RTOS is an operating system suitable for real-time processing. Meanwhile, the general-purpose OS such as Android (registered trademark) has more functions compared with the RTOS, although the general-purpose OS takes time to complete activation after power to a digital camera has been turned on. With this configuration, in a case where the digital camera operates exclusively on the general-purpose OS, a problem would occur when a user attempts to capture an image immediately after the power to the digital camera has been turned on. In some cases, it is difficult for the user to capture an image in a timing desirable for the user because the general-purpose OS has not been activated in time.
An electronic device described in Japanese Patent Application Laid-Open No. 2012-146052 allows a camera function operating on the RTOS to be activated immediately after the power to the camera has been turned on, and thereafter, starts activation processing of the general-purpose OS in a background. In a case where the electronic device detects an imaging instruction during a period until completion of the activation processing of the general-purpose OS, the electronic device stops the activation processing of the general-purpose OS. Subsequently, this electronic device uses the RTOS to control the camera function so as to execute imaging processing. After executing imaging by the RTOS, the electronic device restarts activation processing of the general-purpose OS.
In the electronic device disclosed in Japanese Patent Application Laid-Open No. 2012-146052, however, an imaging instruction has not been generated at a time when the electronic device is using the RTOS to control the camera function and performing framing operation and zooming operation in response to a user's instruction, and thus, the activation processing of the general-purpose OS is continuing without interruption. With this configuration, in a case where the activation processing of the general-purpose OS is completed while the user is performing imaging preparation operation using the camera function of the RTOS, the camera function is switched to the camera function operating on the general-purpose OS causing the setting on the RTOS to be cancelled. This might lead to an interference with the user's imaging operation. In short, imaging processing in a case where imaging operation is performed immediately after the power has been turned on can be a problem.